Planet Earth's closest black hole has emitted an intensely powerful and "violent" outburst which would wipe out any human unlucky enough to be hit by it.

The radioactive "wind" was spotted travelling at 3,000km (1,864 miles) during observations of V404 Cygni, that's situated in a part of the Milky Way relatively close to the Earth.

It went into a bright and violent outburst in June 2015 after more than 25 years of lying dormant, astronomers have reported.

The discovery was made using the 10.4m Gran Telescopio Canarias (GTC) - the biggest optical-infrared telescope in the world, situated at the Roque de los Muchachos Observatory in the Canary Islands.

The results, which are published today in Nature, show that the wind, detected for the first time in a system of this type, travelled at a massive 3,000 kilometres per second) and was so speedy it escaped from the gravitational field around the black hole.

Professor Phil Charles, from the University of Southampton, said: "Its presence allows us to explain why the outburst, in spite of being bright and very violent, with continuous changes in luminosity and ejections of mass in the form of jets, was also very brief, lasting only two weeks."

At the end of this outburst the GTC observations revealed the presence of a nebula formed from material expelled by the wind.

This phenomenon, which has been observed for the first time in a black hole, also allows scientists to estimate the quantity of mass ejected into the interstellar medium.

Teo Munoz Darias, a researcher at the Instituto de Astrofisica de Canarias (IAC) and the lead author of the study, said: "The brightness of the source and the large collecting area of the GTC allowed us not only to detect the wind, but also to measure the variation of its properties on time-scales of minutes. The database obtained is probably the best ever observed for an object of this kind.

"This outburst of V404 Cygni, because of its complexity and because of the high quantity and quality of the observations, will help us understand how black holes swallow material via their accretion discs."

V404 Cygni is a black hole within a binary system located in the constellation of Cygnus which is 8,000 light years away.

In such systems, of which less than 50 are known, a black hole of around 10 times the mass of the sun is swallowing material from a very nearby star, its companion star.